Radio switching control



Jan. 13, 1931. L. J. BUTTOLPH 1,733,979

' I RADIO SWITCHING CONTROL Filed Dec. 11, 1926 Op if i i, m1

Paten ted Jan. 13, 1931- UNITED-STATES PATENT 1. 'oF-Fi'c El LEROY J. BU'r'roLrn, OF GRANTWOOD, NEW JERSEY, ASSIGNQR 'ro GENERAL nLnornIo VAPOR LAMP COMPANY, or HOBOKEN, NEW JERSEYQA CORPORATION/P3 NEW JERSEY RADIO SWITCHING-CONTROL Application filed December 11, 1926. Serial No. 154,066.

The present invention relates to control means in electric circuits connected to sound amplification apparatus such as radio receiving circuits and'the like. The invention relates. more particularly to switching connections for cutting off and cutting in volume control apparatus in the sound amplification circuit before the sound amplification reaches a predetermined point, or immediately upon the beginning of tuning from a minimum volume position of the tuned part.

Various objects and advantages of the invention will be obvious from the following particular description of one form of apparatus embodying the invention or from an inspection of the accompanying drawing; and the invention also consists in certain new and novel features of construction and combinations of parts hereinafter set forth and 29 claimed.

In the accompanying drawing there is shown for purposes of illustration one form of device embodying the invention and a circuit therefor, in which v Fig. 1 is a diagrammatic view in perspective showing somewhat diagrammaticallyan embodiment of the invention,

Fig. 2 is an end view of the apparatus of Fig. 1 in a different position of adjustment,

Fi 3 is a diagram of connections of apparatus including the embodiment of the invention. v

. In Fig. 1 the adjustable coil 1 which is loosely coupled with the coil 3 is mounted on the tuning shaft 5' which carries at one end the adjusting knob 7 and at the other end the part of a circuit in which it is used. The

said coil 1 is at a position of minimum coupling with said coil 3 and the switch 10 is in the open circuit position. The inductance coil 1 which iscoupled with coil 3, may be moved in a clockwise direction. It will be seen as indicatedin Fig. 2 that the switch 10 will be closed before any effective coupling will be made such as to roduce any substantial volume from ampli ying apparatus connected thereto or theret-hrough, it being understood of course that at a minimum coupling no perceptible or at least small volume I of sound will be produced. It will thus be seen that in a radio'receiving set havin a loudspeaker which would be disagreeably loud if turned on suddenly at full volume, such a mode of operation will be prevented because the energizing switch will be closed 'at a point near the point of production of minimum volume and will then remain closed, so that the volume of sound must'be increased from a minimum to the maximum without the possibility of the circuit suddenly being closed to produce the maximum volume of sound. In Fig. 3 of the drawing the switch 10' is connected in series with the filament '12-, and the A battery 14. Theswitch 10 "through the shaft 5'is mechanically connected to the movable coil lwhich is loosely coupled with the coil 3which is connected-in series between the audionplate 16 on one side and through the telephone or loud speaker 18 and B battery 20 to'a point between said filament 12 andsaid switch 10. The grid 22 of the audion tube of which the Ifilament12 and plate-16; are other elements is connected through the gridleak and condenser unit-24 to said stationary coil 1 of 'thetuned couple,

thence through the coupling coil 26 and from there to point between said filament 12 and saidiA' battery '14. An antenna 30 connects through a coil 32 which is in tuned coupled relation to said coil 26 thence through" the .evariable condenser 34*to a ground'connec- .tion. This circuit has been used toi llustrate the application of the present invention but it is to be'understood that the inv'ention can i i a be applied with the switch 10' connected "in mercury switch 10 for connection to a control any .part of the circuit to provide-that the circuit is not closed except when the variable elements are in such relation as to provide that sound production is brought from a minimum through gradations to any full or powerful Value;

purpose. It has certain advantages highly desirable inaradio receiving setfor example because it permits of smooth and gradual adjustment of a current control element without any restriction on a continued and gradual adjustment such as would be made by a switch having for example comparatively stiff spring connection members. In securing this effect, I am not limited either as to the type of volume control or the type of switch device used. The volume control may for example be either a variable regeneration control, a variable filament control for the radio amplifier tubes, a potentiometer on the secondary of an audio-transformer, or any of the other methods of volume control known to the art. As an alternative, there might be shown in place of a variable tickler coil, a variable condenser used as a regeneration control, a variable resistance used as a filament current control or even a variable antenna coupling device in the form of a movable coil. The mercury switch also provides a simple means for keeping the circuit closed through the 90 of movement from minimum to maximum coupling and for breaking the circuit when the element is returned to the uncoupled position.

While I have shown and described and have pointed out in the annexed claims certain novel features of the invention, it will be understood that various omissions, substitutions and changes in the forms, parts and de tails of the devices illustrated and in their operation and connection to and in electric circuits may be made by those skilled in the art without departing from the spirit of the invention.

I claim:

1. In combination in a radio circuit, a source of energy, a work circuit, a variable inductive coupler for energy transfer between said source and said work circuit, and means including a mercury switch actuated simultaneously with said coupler to prevent the initiation of energy transmission from said source to said work circuit except when said coupler is adjusted for minimum energy transfer.

2-. In a radio circuit, a source of energy, a work circuit, a variable inductive coupling between said source and said work circuit for the transfer of energy, means for starting and stopping said energy transfer, and means Wherebysaid energy transfer can be initiated only when there is a minimum of coupling btween said source of energy and said work circuit.

3. In a radio circuit, a source of energy, a work circuit, means for transferring energy from said source to said work circuit, comprising a thermionic tube and a variable coupler, means for closing the filament circuit of said tube to a suitable source of energy, and means whereby current flow through said filament circuit can be initiated only when said coupler is set for a minimum rate of energy transfer.

Signed at Hoboken in the county of Hudson and State of New Jersey this 8th day of December A. D. 1926.

LEROY J. BUTTOLPH. 

